Rear bumper



FIG. 1 is a front view of a rear bumper showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a rear side view thereof.

It will be understood that the broken lines shown in the drawings illustrate portions of the rear bumper that form no part of claimed design. 

CLAIM The ornamental design for a rear bumper, as shown and described. 